[Intel-gfx] [PATCH 0/5] drm/i915: Gen2 PLL fixes

[Bruno Prémont]

Hi Ville,

On Tue, 10 December 2013 Ville Syrjälä wrote:
> On Tue, Dec 10, 2013 at 12:52:27PM +0100, Bruno Prémont wrote:
> > On Mon, 09 December 2013 Ville Syrjälä wrote:
> > > There appear to be some gen2 machines that don't really like the current PLL
> > > limits we have. We also have some accuracy problems with the PLL calculations.
> > > This series aims to eliminate those problems, and at least my 855 machine
> > > seems happier with these patches.
> > > 
> > > Ville Syrjälä (5):
> > >       drm/i915: Extract p2 divider correctly for gen2 LVDS dual channel
> > >       drm/i915: Change N divider minimum from 3 to 2 for gen2
> > >       drm/i915: Increase gen2 vco frequency limit to 1512 MHz
> > >       drm/i915: Fix 66 MHz LVDS SSC freq for gen2
> > >       drm/i915: Decrease gen2 vco frequency minimum to 908 MHz
> > > 
> > >  drivers/gpu/drm/i915/intel_bios.c    |  8 ++++----
> > >  drivers/gpu/drm/i915/intel_display.c | 34 +++++++++++++++++++---------------
> > >  2 files changed, 23 insertions(+), 19 deletions(-)
> > 
> > Here is my dmesg with the 5 patches applied (on top of 3.13-rc3 and
> > the PLL debug patch).
> > 
> > The WARN() are not hit anymore.
> > 
> <snip>
> > [   46.584578] [drm:intel_dump_pipe_config], DPLL = 0x0
> > [   46.584581] [drm:intel_dump_pipe_config], DPLL_MD = 0x0
> > [   46.584583] [drm:intel_dump_pipe_config], FP0 = 0x0
> > [   46.584586] [drm:intel_dump_pipe_config], FP1 = 0x0
> 
> OK, so I think the problem got fixed, but my debug patch wasn't
> all that good since it doesn't dump the values we computed unless
> the clock is off.
> 
> Can you still run this (as root) when the LVDS output is active:
> # intel_reg_read 0x6014 0x6018 0x6040 0x6044 0x6048 0x604c
> 
> intel_reg_read is part of intel-gpu-tools.

Here are the results (when already running under X since previous
my mail):

# intel_reg_read 0x6014 0x6018 0x6040 0x6044 0x6048 0x604c
0x6014 : 0x0
0x6018 : 0x90020000
0x6040 : 0x2140E
0x6044 : 0x2140E
0x6048 : 0x2140E
0x604C : 0x2140E

> I just want to confirm we calculated the DPLL registers correctly.
> I know we at least got close since ther WARN is gone, but by my
> calculations we should get exactly the same as what the BIOS used.

Bruno